The figure describes the variation of swells directed at Punta Brava through an average March, based on 1724 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the most applicable grid node based on what we know about Punta Brava. In this particular case the best grid node is 30 km away (19 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast only 0% of the time. Green and yellow represent increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the prevailing swell direction, shown by the longest spokes, was SSW, whereas the the dominant wind blows from the N. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Punta Brava and away from the coast. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Punta Brava, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical March, swells large enough to cause surfable waves at Punta Brava run for about 100% of the time.
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.